Definition:

LCH

A group of rare disorders in which too many Langerhans cells (a type of white blood cell) grow in certain tissues and organs including the bones, skin, and lungs, and damage them. LCH may also affect the pituitary gland (which makes hormones that control other glands and many body functions, especially growth). LCH is most common in children and young adults. Also called Langerhans cell histiocytosis.